In the transmission of signals (e.g. voice signals) it is known to have U users that transmit at the same time on the same nominal carrier frequency fcarrier, causing a so-called double transmission if U≧2. These U users correspond to U mobile or fixed stations, which transmit respective signals e.g. Double Side-Band full carrier Amplitude Modulated (DSB-AM) voice signals, termed A3E following ITU modulation code.
1 Summary
Double transmissions are a problem especially in Air Traffic Control (ATC) if they remain undetected, because only the strongest signal is perceived by the other side, the remaining signals might be overheard.
In view of the above-described situation, there exists a need for an improved technique that enables to cope with double transmission, while substantially avoiding or at least reducing one or more of the above-identified problems.
This need may be met by the subject matter according to the independent claims. Advantageous embodiments of the herein disclosed subject matter are described by the dependent claims.
According to an embodiment of a first aspect of the herein disclosed subject matter there is provided a method for the detection of more than one signal contained in a receive signal, the method comprising: down-converting the receive signal, thereby providing a down-converted signal in a complex IQ base band; at least partially cancelling the strongest user (user signal) in the down-converted signal, thereby allowing for the detection of a possible secondary user (secondary user signal).
According to an embodiment of a second aspect of the herein disclosed subject matter, there is provided a method of detecting CLIMAX signals, e.g. by detection of the spectral peaks caused by a carrier (e.g. a DSB-AM carrier), e.g. as described in chapter 5.1.
According to an embodiment of a third aspect a computer program product is provided, e.g. in the form of a program element or a computer readable medium comprising a program element, the program product (in particular the program element) being adapted for carrying out, when running on a processor device, the method according to the first aspect or an embodiment thereof.
According to an embodiment of a fourth aspect a receiver of a communication system is provided, the receiver comprising a controller being adapted for carrying out the method according to the first aspect or an embodiment thereof.
According to an embodiment of a fifth aspect a communication system is provided, the communication system comprising a receiver according to the fourth aspect or an embodiment thereof.
According to embodiments of the first aspect, the method is adapted for providing the functionality of one or more of the herein disclosed embodiments and/or for providing the functionality as required by one or more of the herein disclosed embodiments, in particular of the embodiments of the second, third, fourth and fifth aspect.
According to embodiments of the second aspect, the method is adapted for providing the functionality of one or more of the herein disclosed embodiments and/or for providing the functionality as required by one or more of the herein disclosed embodiments, in particular of the embodiments of the first, third, fourth and fifth aspect.
According to embodiments of the third aspect, the computer program is adapted for providing the functionality of one or more of the herein disclosed embodiments and/or for providing the functionality as required by one or more of the herein disclosed embodiments, in particular of the embodiments of the first, second, fourth and fifth aspect.
According to embodiments of the fourth aspect, the receiver is adapted for providing the functionality of one or more of the herein disclosed embodiments and/or for providing the functionality as required by one or more of the herein disclosed embodiments, in particular of the embodiments of the first, second, third and fifth aspect.
According to embodiments of the fifth aspect, the communication system is adapted for providing the functionality of one or more of the herein disclosed embodiments and/or for providing the functionality as required by one or more of the herein disclosed embodiments, in particular of the embodiments of the first, second, third and fourth aspect.
Generally herein, a reference to a user is intended to include a reference to a user signal and vice versa and is used to enhance clarity. For instance, a reference to “the strongest user” includes a reference to “the strongest user signal” and a reference to “a secondary user” includes a reference to “a secondary user signal”.
In the following, exemplary embodiments of the herein disclosed subject matter are described, any number and any combination of which may be realized in an implementation of the herein disclosed subject matter.
As used herein, reference to a program element is intended to include a reference to a set of instructions for controlling a computer system to effect and/or coordinate the performance of the respective method.
The computer program may be implemented as computer readable instruction code by use of any suitable programming language, such as, for example, JAVA, C++, and may be stored on a computer-readable medium (removable disk, volatile or non-volatile memory, embedded memory/processor, etc.). The instruction code is operable to program a computer or any other programmable device to carry out the intended functions. The computer program may be available from a network, such as the World Wide Web, from which it may be downloaded.
The herein disclosed subject matter may be realized by means of a computer program respectively software. However, the herein disclosed subject matter may also be realized by means of one or more specific electronic circuits respectively hardware. Furthermore, the herein disclosed subject matter may also be realized in a hybrid form, i.e. in a combination of software modules and hardware modules.
In the above there have been described and in the following there will be described exemplary embodiments of the subject matter disclosed herein with reference to methods, a computer program product, a receiver and a communication system. It has to be pointed out that of course any combination of features relating to different aspects of the herein disclosed subject matter is also possible. In particular, some features have been or will be described with reference to apparatus type embodiments whereas other features have been or will be described with reference to method type embodiments. However, a person skilled in the art will gather from the above and the following description that, unless other notified, in addition to any combination of features belonging to one aspect also any combination of features relating to different aspects or embodiments, for example even combinations of features of apparatus type embodiments and features of the method type embodiments are considered to be disclosed with this application.
The aspects and embodiments defined above and further aspects and embodiments of the herein disclosed subject matter are apparent from the examples to be described hereinafter and are explained with reference to the drawings, but to which the invention is not limited.